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Re: [ontolog-forum] Just What Is an Ontology, Anyway?

To: <ontolog-forum@xxxxxxxxxxxxxxxx>
From: "sean barker" <sean.barker@xxxxxxxxxxxxx>
Date: Fri, 30 Oct 2009 19:57:53 -0000
Message-id: <B1CEE1D3C4944A6DAD9EAC03B1158F4B@SMB>

Much as I hesitate to disagree with Matthew, when he says "As I said above, 
ontology is about the things in the world, not how we talk about them", I do 
disagree.    (01)

The problem of defining an ontology is surely one of defining the categories 
(words/signs) of things (in the world) that we want to distinguish, and of 
identifying the properties and range of property values that characterise 
those things. A good ontology is one where, if there are a set of distinct 
categories, a thing will be in exactly one category, and will have the 
properties and property values required. (Up to this point, I doubt that we 
disagree).    (02)

In practice, in day-to-day life, there is agreement about many observable 
categories and their properties. The problems come when there are different 
categorizations of observables (such as colour terms) or where category is 
inferred from the observables - for example, the categorization as something 
as a bungalow, where the observables are a building, its windows and doors 
etc. and knowledge is then used to infer bungalow. [This is complicated by 
the need to assess the competence of the observer - does he know the 
difference between a shovel and a spade?]    (03)

I would therefore prefer that an ontology is the result of a dialectic 
between an objective physical world, and a subjective, human constructed 
vocabulary. The development of the vocabulary, in terms of scope and 
precision, involves reassessment of the observable world, both as to the 
adequacy and completeness of the observables that we count as the properties 
of the category, and to the exactitude and certainty of the observables.    (04)

The claim that a particular ontology is an objective model of the world is 
essentially a claim that the dialectic has converged to the point that the 
category are stable, and the list of essential properties agreed. It is 
objective in the sense that any competent member of the linguistic community 
will classify things in the ontology in the same way, and identify the same 
properties in the same way. Further, a translation for another linguistic 
community is likely to be comprehensible, even if they do not agree with the 
categorization (think, for example, of categories of family relationships, 
and how they would be treated by tribal societies not based on the nuclear 
family).    (05)

The problem comes when the ontology contains categories which are inferred 
from the observables or defined by convention. For example, "a major fire", 
"an accident", "a riot", "a medical specialist", "a qualified alternative 
therapist".    (06)

Thus, while I would agree that there are some objective models, such as the 
chemical elements, and convention based models with objective properties, 
such as units of measure, there are also non-objective models, such as the 
categories in a Dewey Decimal System, or the categories of document that 
company procedures recognise. In practice, much of what those of us in 
business are interested in is the non-objective, business categories. In 
this case, the basic categories should be exactly the labels for alternative 
paths in a business process. To these will be added the categories that 
support the heuristics of the particular community, either subdividing a 
single category into sub-categories which support local linguistic 
conventions (for example, Waterloo station is a single category from the 
fares point of view, but two different stations when you want to get a 
train) or the development of meta-categories (super classes).    (07)

Consequently, saying an ontology is either about things the world OR about 
how we talk about them is to make a false dichotomy.    (08)

Sean Barker
Bristol    (09)

From: ontolog-forum-bounces@xxxxxxxxxxxxxxxx 
[mailto:ontolog-forum-bounces@xxxxxxxxxxxxxxxx] On Behalf Of Matthew West
Sent: 30 October 2009 08:35
To: '[ontolog-forum] '
Subject: Re: [ontolog-forum] Just What Is an Ontology, Anyway?    (010)

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But then how do we account for the diverse viewpoints going into the system 
from multiple users?  We all agree that each user has a unique ontology of 
her personal world.  We know that subjectivity gets squeezed into the 
tightest databases with the strictest controls.    (015)

MW: You  can't. And in fact the problem really is just how do you impose 
sufficiently strict controls such that the range of meaning is sufficiently 
small that sufficiently accurate communication is possible.    (016)

You must.  As John Sowa is fond of saying, people play language games.    (017)

MW: But computers don't.    (018)

Those games are more complicated than we can decipher from signs alone.  So 
one enterprise level purpose of each subjective personal ontology is to 
"correct" the personal viewpoint, projecting it back into the enterprise 
ontology.    (019)

MW: This is essentially the process of agreeing the enterprise ontology, or 
aligning with it.    (020)

But note that if you project the disjunction of all personal ontologies to 
make up the enterprise ontology, you have to match common items shared among 
personal ontologies.    (021)

MW: I don't know anyone who would do it like that. Much more likely is that 
a few people determine the enterprise ontology, and then others are left 
with aligning their own viewpoint with it.    (022)

For example, probably most or all normal English speakers think of fluids in 
one way, solids in another and gases in a third.  The English language 
reflects the way we talk about the things belonging to these different 
classes.    (023)

MW: One has to be very careful about this. Language includes lots of old 
ways of thinking about things that are not accurate. Ontology is about 
modeling how things are in the world, not how  we talk about them.    (024)

So there is clearly a linguistic common ontology of objects and classes that 
constitutes everyday usage.    (025)

MW: No there is not, because with everyday language you can express any of 
the ontologies you might find. Words have such a variety of usages, that it 
can be difficult to accurately determine the meaning of words out o f 
context, and sometimes even in context.    (026)

That can be part of the enterprise ontology.  But its part of EVERY language 
competent ontology.    (027)

MW: I've no idea what that might be. As I said above, ontology is about the 
things in the world, not how we talk about them.    (028)

So the enterprise ontology also includes things specific to the objects 
about which that enterprise is concerned.    (029)

Leading to the conclusion that the enterprise ontology will have to be 
multilayered, scalloped like a 50's hot rod into component ontologies for 
each viewpoint and each group of viewpoints.    (030)

MW: Well yes you can do that (maybe), but at prohibitive expense because of 
the interfaces between vewpoints, so I doubt if anyone will. This is back to 
why a meeting of a French, Italian, German and Spanish people will conduct 
business in English.    (031)

Regards    (032)

Matthew West
Information  Junction
Tel: +44 560 302 3685
Mobile: +44 750 3385279
http://www.matthew-west.org.uk/    (033)

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